I got the below error

{
    "code" : "bad_request",
    "context_info" : 
    {
        "errors" : 
        r
            {
                "message" : "Invalid value '{'. Entity body should be a correctly nested resource attribute name/value pair",
                "name" : "entity-body",
                "reason" : "invalid_parameter"
            }
        ]
    },
    "help_url" : "http://developers.box.com/docs/#errors",
    "message" : "Bad Request",
    "request_id" : "c59r7lhc3wmsrktn",
    "status" : 400,
    "type" : "error"
}

Hi Bruno,

I'm not sure exactly what tools you're using to upload the file, curl, postman, python SDK, etc, so I'll build the example using postman, and because this is uploading a file, I'll include the curl sample.

Take a look at our API documentation about upload:

curl -i -X POST "https://upload.box.com/api/2.0/files/content" \

     -H "Authorization: Bearer <ACCESS_TOKEN>" \

     -H "Content-Type: multipart/form-data" \

     -F attributes='{"name":"Contract.pdf", "parent":{"id":"11446498"}}' \

     -F file=@<FILE_NAME>

Consider I have an uploads folder:

Notice the folder ID: 199908799409

I want to upload file /Users/rbarbosa/Downloads/box-dev-logo.png to the above folder as Photo.png.

The curl command would look like:

curl --location 'https://upload.box.com/api/2.0/files/content' \
--header 'Content-Type: multipart/form-data' \
--header 'Authorization: Bearer y0swqp3X7jETkkiyqRHu6zATHUT8aZJF' \
--form 'attributes="{
  \"name\": \"Photo.png\",
  \"parent\": {
    \"id\": \"199908799409\"
  }
}"' \
--form 'file=@"/Users/rbarbosa/Downloads/box-dev-logo.png"'

And the output is:

{
  "total_count": 1,
  "entries": r
    {
      "type": "file",
      "id": "1170390912067",
      "file_version": {
        "type": "file_version",
        "id": "1274952136867",
        "sha1": "64ba1fbdc00d78945d69db3b6190be429dee5a04"
      },
      "sequence_id": "0",
      "etag": "0",
      "sha1": "64ba1fbdc00d78945d69db3b6190be429dee5a04",
      "name": "Photo.png",
      "description": "",
      "size": 8974,
      "path_collection": {
        "total_count": 2,
        "entries": r
          {
            "type": "folder",
            "id": "0",
            "sequence_id": null,
            "etag": null,
            "name": "All Files"
          },
          {
            "type": "folder",
            "id": "199908799409",
            "sequence_id": "0",
            "etag": "0",
            "name": "Uploads"
          }
        ]
      },
      "created_at": "2023-03-21T15:12:05-07:00",
      "modified_at": "2023-03-21T15:12:05-07:00",
      "trashed_at": null,
      "purged_at": null,
      "content_created_at": "2023-03-21T15:12:05-07:00",
      "content_modified_at": "2023-03-21T15:12:05-07:00",
      "created_by": {
        "type": "user",
        "id": "18622116055",
        "name": "Rui Barbosa",
        "login": "barduinor@gmail.com"
      },
      "modified_by": {
        "type": "user",
        "id": "18622116055",
        "name": "Rui Barbosa",
        "login": "barduinor@gmail.com"
      },
      "owned_by": {
        "type": "user",
        "id": "18622116055",
        "name": "Rui Barbosa",
        "login": "barduinor@gmail.com"
      },
      "shared_link": null,
      "parent": {
        "type": "folder",
        "id": "199908799409",
        "sequence_id": "0",
        "etag": "0",
        "name": "Uploads"
      },
      "item_status": "active"
    }
  ]
}

In this case the attributes of the request are:

{
  "name": "Photo.png",
  "parent": {
    "id": "199908799409"
  }
}

name: the name of the file to be stored at box. notice it is not the same original filename (but it can be)

parent, id: the id of the folder to where you are uploading the file.

The file it self is uploaded using the multipart/form-data encoding, and depends on the tool you are using.

Postman for example allows you to select a file from the file system:

and curl just uses the --form flag.

All of our SDK's have methods to facilitate this.

Hope this helps, let us know.

Best regards